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Logo of thijTexas Heart Institute JournalSee also Cardiovascular Diseases Journal in PMCSubscribeSubmissionsTHI Journal Website
Tex Heart Inst J. 2010; 37(4): 503.
PMCID: PMC2929856

Isolated Cleft of the Mitral Valve

Its Pathogenic Relationship with Endocardial Cushion Defects

To the Editor:

We read the interesting and detailed paper by Zhu and colleagues1 in a recent issue of your journal. The authors report on the anatomic aspects, the clinical course, and the surgical results associated with isolated cleft of the mitral valve in 90 patients. It is noteworthy that, among their 90 patients, 26 (28.8%) had trisomy 21, a genetic syndrome known to be frequently associated with endocardial cushion defects in a pathogenic relationship.2

The authors correctly report that classic isolated cleft of the mitral valve is associated neither with ostium primum atrial septal defect nor with inlet ventricular septal defect and that the mitral cleft is oriented towards the left ventricular outflow tract, rather than towards the inlet septum (as is seen in the cleft of patients with endocardial cushion defects3). In spite of these anatomic differences, the high prevalence of Down syndrome in patients with isolated cleft of the mitral valve suggests, in our opinion, the existence of a pathogenic link with endocardial cushion defects4 in a subgroup of these patients. Moreover, the well-known high frequency of isolated mitral clefts in families with atrioventricular canal defect can also be explained by a developmental connection between isolated cleft of mitral valve and endocardial cushion defects.5,6

Elena Boccuzzi, MD
Emanuela Casinelli, MD
Paolo Versacci, MD
Bruno Marino, MD
Department of Pediatrics, “Sapienza” – University of Rome, Rome, Italy


1. Zhu D, Bryant R, Heinle J, Nihill MR. Isolated cleft of the mitral valve: clinical spectrum and course. Tex Heart Inst J 2009;36(6):553–6. [PMC free article] [PubMed]
2. Marino B, Vairo U, Corno A, Nava S, Guccione P, Calabro R, Marcelletti C. Atrioventricular canal in Down syndrome. Prevalence of associated cardiac malformations compared with patients without Down syndrome. Am J Dis Child 1990;144(10):1120–2. [PubMed]
3. Kohl T, Silverman NH. Comparison of cleft and papillary muscle position in cleft mitral valve and atrioventricular septal defect. Am J Cardiol 1996;77(2):164–9. [PubMed]
4. Digilio MC, Marino B, Giannotti A, Dallapiccola B. Familial atrioventricular septal defect: possible genetic mechanism. Br Heart J 1994;72(3):301. [PMC free article] [PubMed]
5. Disegni E, Pierpont ME, Bass JL, Kaplinsky E. Two-dimensional echocardiography in detection of endocardial cushion defect in families. Am J Cardiol 1985;55(13 Pt 1):1649–52. [PubMed]
6. Cousineau AJ, Lauer RM, Pierpont ME, Burns TL, Ardinger RH, Patil SR, Sheffield VC. Linkage analysis of autosomal dominant atrioventricular canal defects: exclusion of chromosome 21. Hum Genet 1994;93(2):103–8. [PubMed]

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